Blow molded case with retaining structure and system for creating same

ABSTRACT

A method and apparatus for blow molding a case for housing an object, such as a tool, is disclosed generally comprising first and second mold portions located adjacent each other to create separate cavities for forming base and lid portions of a case. The second mold surface includes a protuberance for creating a protrusion on an outer wall of the case during blow molding, which serves to restrain the movement of an object that is received in a hole in the corresponding inner wall of the case. In certain embodiments, the protrusion corresponds to at least part of the outline of the object or an aperture in the object. In some embodiments, the protrusion is positioned to engage an edge of the object to prevent movement.

RELATED APPLICATIONS

This patent application is a continuation-in-part of currently pending U.S. patent application Ser. No. 10/958,824, filed Oct. 5, 2004.

FIELD OF THE INVENTION

The present invention relates to blow molded cases. More specifically, the invention relates to double wall blow molded cases having a retaining structure for engaging an object placed in the case, as well as a system for creating such cases.

BACKGROUND OF THE INVENTION

The use of blow-molding as a method for manufacturing various sorts of articles is generally well known. Typically, this process involves the use of a mold consisting of two separate halves or portions having cavities of particularly desired shapes and sizes. Usually, one extrudes a large-diameter, sealed tube of molten material (commonly referred to as a “parison”), places the tube between the mold halves, and closes the mold around the tube. Fluid pressure is then introduced into the tube, forcing the molten tube against the walls of the cavities, conforming the tube to the shape thereof. The pressure is maintained until the molten material cools and solidifies. The pressure is then released, the mold halves are pulled apart, and the hardened article is ejected therefrom.

One such article that is commonly manufactured in this manner is double wall cases. By producing cases in this manner, one is able to produce a device that is capable of carrying and protecting tools placed inside the case that has a multitude of desirable physical characteristics—such as rigidity, scuff resistance, and impact absorption—yet that is relatively inexpensive to manufacture. Typically, these cases will be formed using the process described above, where one mold half forms the exterior of both the base and lid portions of the case, while the other mold half forms the interior of both base and lid portions. Usually, the mold half forming the exterior of the case forms a wall with a smooth, attractive shape, while the mold half that forms the interior of the case is often molded with compartments to hold specific contents, such as, for example, a pistol-type soldering iron and various tips therefore. In fact, a particular advantage of manufacturing cases in this way is that the walls formed by the two mold halves do not need to match, as the space between these walls is filled with air.

One disadvantage of these cases, however, is that, due to their double wall nature, they tend to be both heavy and cumbersome. Accordingly, it has been suggested to cut out sections of the interior walls of the case in order to utilize the wasted volume of space between the double walls. By doing so, the case can be made smaller in light of the fact that this previously unused space is now being used to house the tool. Moreover, by removing sections of the walls, the case also decreases significantly in weight. As a result, it is also much easier to mold the design of the interior of the case, as it is no longer necessary to create deep molded compartmentation, and fewer molding rejects also result.

An example of this approach is disclosed in U.S. Pat. No. 3,317,955 to Schurman, et al., which discloses the earliest known double wall case blow-molded case, illustrating a rectangular cutout of most of the inside wall of the base portion. Another example is disclosed in U.S. Pat. No. 3,327,841 to Shurman, et al., which illustrates a partial cutout shaped to accommodate the outline of a pistol-type soldering gun. The gun is further supported by a cradle molded in the outside wall of the base portion of the case, while the space under the uncut portion of the inside base is usable for storage of an electric cord, thereby maximizing the utilization of what was previously wasted, unused space.

In order to create these spaces, a section of the inner wall of the blow molded case must be removed, which can achieved in any of various ways. Because the blow molding process involves the use of a parison with a continuous, unbroken surface, the mold itself cannot produce any holes in the blow-molded wall other than the hole or holes through which the fluid pressure is introduced. Therefore, removing these sections typically involves an additional manufacturing step, where these wall sections are cut or burned after the blow molding process is completed and the case has been ejected from the mold. For example, cutting the inner wall was often accomplished with the use of a small circular saw blade mounted to a router and guided by a molded vertical lip surrounding the area to be cut. The router was fixed and the case was moved around the router axis by hand or by mechanical means. Round holes are often cut with hole saws, or occasionally, are burned. Another, more improved method of removing a section of the inner wall of the case is to punch a hole in this wall during the blow molding process, such as with the system disclosed herein and in co-pending U.S. patent application Ser. No. 10/958,824.

When a section of the inner wall is removed in one of these ways in order to make this extra space available to accommodate any objects that are to be carried in the case, the entire space between the inner and outer walls becomes accessible by the object. Accordingly, when the case is carried, the object will slide and bounce around within the case. This problem can, in some cases, be solved by punching a hole in the inner wall that corresponds to the shape of the object to be placed in the case, and may include a sidewall substantially perpendicular to, and running along the perimeter of, this shaped hole, thereby providing a press fit insertion of the object into the hole. However, though useful in many applications, this solution may not be desirable in all situations. For example, the aforementioned solution not only requires very particular cutting or punching, but, in the case of objects that are very thick, it may only work if holes are cut or punched in both the base portion and the lid portion. Additionally, it requires a significant portion of the inner wall to remain intact, thereby increasing the weight of the case. Therefore, depending on the size of the object, and thus, how much of the wall would have to remain intact, this may or may not be an optimal solution. Additionally, if other objects (such as, for example, a power cord) are also to be housed by the case, separate holes may have to be punched or otherwise created in the inner wall in order to provide space for accommodating these objects. Finally, in some cases, it may just be desirable to have an additional means of retaining the object in addition to the aforementioned solution.

What is desired, therefore, is a blow-molded case that is double walled, but is not heavy or cumbersome. What is also desired is a case that is easy and inexpensive to manufacture. What is further desired is a blow-molded case that prevents an object from bouncing or moving around inside the case. What is also desired is a case that does not necessarily require punching or cutting holes that specifically correspond to the shape of the object, or a second hole in the lid portion of the case in addition to the hole in the base portion, or separate additional holes for accessories that are also to be housed by the case.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a double wall case that utilizes the space between the walls of the case.

It is a further object of the present invention to provide a double wall case that restrains an object to be carried therein to prevent it from moving excessively within the case.

It is yet another object of the present invention to provide a double wall case that can achieve the aforementioned objectives even if the hole created in the inner wall of the case does not specifically correspond to the shape of an object to be carried therein.

It is still another object of the present invention to provide a double wall case that can achieve the aforementioned objectives even if a second hole is not created in the lid portion of the case.

It is another object of the present invention to provide a double wall case that can accommodate additional accessories without having to create separate, additional holes in the inner wall of case.

In order to overcome the deficiencies of the prior art and to achieve at least some of the objects and advantages listed, the invention comprises an apparatus for creating a blow-molded case for housing an object, including a mold comprising first and second mold portions that, when located adjacent each other, at least partially define first and second cavities having first and second cavity surfaces, respectively, against which first and second parts of a blow molded case are blown during blow molding, respectively, wherein the first mold portion has a first mold surface against which inner walls of the first and second parts of the blow molded case are blown, wherein the second mold portion has a second mold surface against which outer walls of the first and second parts of the blow molded case are blown, wherein the second mold surface includes a protuberance extending into the first cavity, around which the outer wall of the first part of the blow-molded case is formed during blow molding to create at least one protrusion extending from the outer wall toward the inner wall of the first part of the blow molded case, and a punch having a punching surface, wherein, when the punch is in an unactivated position, the first cavity surface includes at least part of the first mold surface and at least part of the punch and, when the punch is in an activated position, at least part of the punch is extended past the inner wall of the first part of the blow-molded case and inside the first cavity such that a hole is created in the inner wall of the first part of the blow-molded case.

In another embodiment, the invention comprises a method for creating a blow-molded case for housing an object, including providing a first mold portion having a first mold surface, providing a second mold portion having a second mold surface with at least one protuberance, moving the first mold portion adjacent to the second mold portion, thereby at least partially enclosing first and second cavities having first and second cavity surfaces, respectively, blowing a first wall of the blow-molded case against the first cavity surface, thereby creating a first case portion comprising an inner wall and an outer wall having a protrusion extending towards the inner wall, blowing a second wall of the blow-molded case against the second cavity surface, thereby creating a second case portion comprising an inner wall and an outer wall, and creating a hole in the inner wall of the first case portion.

In yet another embodiment, the invention comprises a blow-molded case for housing an object, including a double wall base portion having an inner wall and an outer wall, and a double wall lid portion connected to the base portion, the lid portion having an inner wall and an outer wall, wherein the inner wall of at least one of the portions has a hole for receiving the object, and wherein the outer wall of the at least one portion having the hole in the inner wall thereof includes a protrusion for engaging the object extending toward the inner wall having the hole therein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a tool case in the open position made in accordance with the invention.

FIG. 1B is a perspective view of the tool case of FIG. 1A in the closed position.

FIG. 1C is a perspective view of the base portion of the tool case of FIG. 1A.

FIG. 1D is a perspective view of the base portion of the tool case of FIG. 1A.

FIG. 2 is a perspective view of an apparatus in accordance with the invention for making the tool case of FIGS. 1A-D.

FIG. 3A is a side view of one embodiment of the apparatus of FIG. 2 in an open position.

FIG. 3B is a side view of the apparatus of FIG. 3A in a closed position.

FIG. 4A is a cut-away, cross-sectional view of part of one embodiment of the apparatus of FIG. 3B where a punch is in an unactivated position.

FIG. 4B is a cut-away, cross-sectional view of the apparatus of FIG. 4A where a punch is in an activated position.

DETAILED DESCRIPTION OF THE DRAWINGS

The basic components of one embodiment of a double wall blow molded tool case in accordance with the invention are illustrated in FIG. 1A. As used in the description, the terms “top,” “bottom,” “above,” “below,” “over,” “under,” “above,” “beneath,” “on top,” “underneath,” “up,” “down,” “upper,” “lower,” “front,” “rear,” “back,” “forward” and “backward” refer to the objects referenced when in the orientation illustrated in the drawings, which orientation is not necessary for achieving the objects of the invention.

The case 10 includes a double wall base portion 12 and a double wall lid portion 14. The base portion 12 has a punched hole 20 in its inner wall 22 that corresponds to the outline of an object, such as a tool, to be housed by the tool case 10. Accordingly, the hole 20 and the space between the inner wall 22 and the outer wall 24 provide a cavity 26 in which the tool can be placed.

Similarly, the lid portion 14 includes a punched hole 30 in its inner wall 32. Accordingly, the hole 30 and the space between the inner wall 32 and outer wall 34 provide a cavity 36 for accommodating the top of the tool when the tool case 10 is closed, as shown in FIG. 1B. In certain advantageous embodiments, the hole 30, like the hole 20, corresponds to the outline of the tool to provide a more secure fit.

In some embodiments, a sidewall 40 substantially perpendicular to the plane of the punched hole 20 runs along the perimeter of the hole 20, providing a press fit insertion of the tool into the cavity 26. Additionally, in certain embodiments, an additional punched aperture 42, which may be a through hole or a blind hole, is provided to permit accessories—such as, for example, drill bits, or, as another example, a power cord—to be stored therein. In some of these embodiments, a flange 44 is provided adjacent the hole 20 and aperture 42 in order to provide for greater rigidity. Depending on the particular embodiment and on the particular tool for which the tool case 10 is designed, one or more of the above-described features may be provided in the lid portion 14 in addition to, or in lieu of, the presence of these features in the base portion 12.

The base portion 12 has at least one protrusion 46 in the outer wall 24, which extends inwardly toward the inner wall 22, for engaging the tool. As shown in FIG. 1A, in some embodiments, the protrusion 46 is specifically sized and shaped to correspond to a particular portion of the tool, such as a handle, and may be shaped to fit into a particular aperture or recess thereof. In other embodiments, as illustrated in FIG. 1C, a protrusion 47 is provided that is merely shaped to correspond to a particular portion of the outline of the tool in order to help keep the tool in place without having to have the punched hole 20 correspond to the exact shape of the tool along the entire outline thereof. As shown in FIG. 1D, in still other embodiments, protrusions 48 are provided that do not necessarily correspond to any outline or aperture of the tool, but are merely positioned at a location that corresponds to the length or width of the tool in order to restrain its movement. In this way, various compartments may be created for various objects, such as a main section 45 for the tool and an auxiliary section 49 for a cord or other accessory.

As illustrated in FIG. 2, an apparatus for creating the tool case 10 of FIG. 1 comprises a mold 50 including a first mold portion 52 and a second mold portion 54. As shown in FIGS. 3A-B, the first mold portion 52 includes first and second punches 56, 58 having first and second punching surfaces 66, 68, respectively. When the first and second mold portions 52, 54 are separated, such as when a parison is being disposed in the mold 50, the first and second punches 56, 58 are in an unactivated position, as shown in FIG. 3A. As illustrated in FIG. 3B, when the first and second mold portions 52, 54 are moved adjacent each other (i.e., when the mold 50 is closed), the first and second punches 56, 58 remain in the unactivated position while the parison is being injected with blowing fluid. Accordingly, portions of the first and second punches 56, 58 form part of the surfaces against which the walls of the blow molded case are blown. Later, when it is desired to punch holes in the walls of the blow molded case, the first and second punches 56, 58 are moved to an activated position, as shown in phantom in FIG. 3B.

The operation of the mold portion 52, 54 and punches 56, 58 is illustrated in FIGS. 4A-B. When the first mold portion 52 is adjacent the second mold portion, a cavity 70 is formed in each of the base and lid portions of the mold 50. For example, referring to FIG. 4A, when the punch 56 is in the unactivated position, the cavity 70 has a cavity surface 80 comprised of the mold surface 72 of the mold portions 52, 54 and part of the punch 56. This cavity surface 80 defines the cavity 70. When blowing fluid is injected into the parison, the wall of the blow molded case is blown against the cavity surface 80.

After a predetermined time interval, the punch 56 is moved from an unactivated position to an activated position, as illustrated in FIG. 4B. When this occurs, the punch 56 is extended past the wall of the blow molded case and into the cavity 70, thereby creating a hole in the wall of the blow molded case. The punch 56 has a punching surface 76 corresponding to the outline of the tool to be housed in the tool case 10, and thus, a hole in the shape of the tool is created in the wall of the blow molded case 10. In certain advantageous embodiments, the punching surfaces of both punches 56 and 58 correspond to the outline of the tool. By removing a large section of the walls of the blow molded case 10 at this stage, drainage of the blowing fluid is almost instantaneous. Similarly, large volumes of air can be quickly circulated inside the case 10, quickly cooling and solidifying the walls of the case. In these ways, the time required for the blow molding cycle is greatly reduced.

In some embodiments, when the punch 56 is in the unactivated position, the punch 56 protrudes out beyond the mold surface 72 into the cavity 70, as shown in FIG. 4A. As a result, when the wall of the blow molded case 10 is blown against the cavity surface 80 (which includes part of the punch 56), the wall of the case 10 is formed around the punch 56. In this way, a recessed portion is formed in the wall of the case. Accordingly, when the punch is moved to the activated position (thereby punching the tool-shaped hole 20 in the wall of the case 10 as shown in FIG. 4B) the sidewall 40 remains along the perimeter of the tool-shaped hole 20. This permits a tighter, press-fit insertion of the tool into the cavity 26.

The second mold portion 54 includes a protuberance 84 that extends into the cavity 70. The protuberance 84 can be any shape or size appropriate to create the desired protrusion in the wall of the case. Accordingly, when the wall of the blow molded case is blown against the cavity surface 80, a protrusion, such as protrusions 46, 47, or 48, is created. In certain of these embodiments, the boss 84 corresponds to a portion of the outline of the tool to be housed in the case 10, or an aperture thereof, in order to create a particularly sized or shaped protrusion as previously described.

In certain advantageous embodiments, the first mold portion 54 includes a protuberance 86 so that the wall of the blow molded case 10 is formed therearound in a manner similar to boss 84, thereby producing an aperture in the wall of the case 10, such as aperture 42. In some of these embodiments, the boss 86 is specifically configured to produce an aperture adapted to receive an accessory of the tool, such as a power cord, drill bits, etc.

In some embodiments, at least one additional punch is provided in addition to the first and second punches 56, 58. Like punches 56, 58, these additional punches, when in an unactivated position, form part of the cavity surface 80 and, when in an activated position, extend out beyond the mold surface 72 to create an aperture in the wall of the blow molded case. Depending on the particular tool to be housed in the case 10 and the particular function desired, the aperture can be a through hole or a blind hole, and can be specifically configured to produce an aperture adapted to receive an accessory of the tool.

In certain advantageous embodiments, the mold surface 72 includes a recess 88 adjacent the punch 56 so that, when the wall of the blow molded case is blown against the mold surface 72, flange 44 is formed, thereby providing greater rigidity to the inner wall 32 of the case 10.

It should be understood that the foregoing is illustrative and not limiting, and that obvious modifications may be made by those skilled in the art without departing from the spirit of the invention. Accordingly, reference should be made primarily to the accompanying claims, rather than the foregoing specification, to determine the scope of the invention. 

1. An apparatus for creating a blow-molded case for housing an object, comprising: a mold comprising first and second mold portions that, when located adjacent each other, at least partially define first and second cavities having first and second cavity surfaces, respectively, against which first and second parts of a blow molded case are blown during blow molding, respectively; wherein said first mold portion has a first mold surface against which inner walls of the first and second parts of the blow molded case are blown; wherein said second mold portion has a second mold surface against which outer walls of the first and second parts of the blow molded case are blown; wherein said second mold surface includes a protuberance extending into said first cavity, around which the outer wall of the first part of the blow-molded case is formed during blow molding to create at least one protrusion extending from the outer wall toward the inner wall of the first part of the blow molded case; and a punch having a punching surface, wherein, when said punch is in an unactivated position, the first cavity surface includes at least part of the first mold surface and at least part of said punch and, when said punch is in an activated position, at least part of said punch is extended past the inner wall of the first part of the blow-molded case and inside said first cavity such that a hole is created in the inner wall of the first part of the blow-molded case.
 2. The apparatus of claim 1, wherein the outer surface of said protuberance corresponds to at least part of the outline of the object.
 3. The apparatus of claim 2, wherein the outline of the object is the outline of a tool.
 4. The apparatus of claim 1, wherein the outer surface of said protuberance corresponds to the outline of an aperture in the object.
 5. The apparatus of claim 1, wherein said protuberance is located at a position in said second mold surface such that the corresponding protrusion formed therearound is positioned to engage an edge of the object to prevent movement of the object within the case.
 6. The apparatus of claim 5, wherein the position of said protuberance corresponds to at least one of a length and a width of the object.
 7. The apparatus of claim 1, wherein at least part of the punching surface of said punch corresponds to at least part of the outline of the object, such that the first hole created in the first wall of the blow-molded case corresponds to at least part of the outline of the object.
 8. The apparatus of claim 1, wherein the blow-molded case comprises a base portion formed in said first cavity and a lid portion formed in said second cavity.
 9. A method for creating a blow-molded case for housing an object, the method comprising: providing a first mold portion having a first mold surface; providing a second mold portion having a second mold surface with at least one protuberance; moving the first mold portion adjacent to the second mold portion, thereby at least partially enclosing first and second cavities having first and second cavity surfaces, respectively; blowing a first wall of the blow-molded case against the first cavity surface, thereby creating a first case portion comprising an inner wall and an outer wall having a protrusion extending towards the inner wall; blowing a second wall of the blow-molded case against the second cavity surface, thereby creating a second case portion comprising an inner wall and an outer wall; and creating a hole in the inner wall of the first case portion.
 10. The method of claim 9, further comprising the step of providing a punch, wherein the step of creating a hole comprises extending at least part of the punch through the inner wall of the first case portion and into the first cavity.
 11. The method of claim 9, wherein the punch includes a punching surface, at least part of which corresponds to at least part of the outline of the object, such that the hole corresponds to at least part of the outline of the object.
 12. The method of claim 9, wherein the outer surface of the protuberance corresponds to at least part of the outline of the object.
 13. The method of claim 12, wherein the outline of the object is the outline of a tool.
 14. The method of claim 9, wherein the outer surface of the protuberance corresponds to the outline of an aperture in the object.
 15. The method of claim 9, wherein the protuberance is located at a position in the second mold surface such that the corresponding protrusion formed therearound is positioned to engage an edge of the object to prevent movement of the object within the case.
 16. The method of claim 15, wherein the position of the protuberance corresponds to at least one of a length and a width of the object.
 17. The method of claim 9, wherein the step of creating a first case portion comprises creating a base portion and the step of creating a second case portion comprises creating a lid portion.
 18. A blow-molded case for housing an object, comprising: a double wall base portion having an inner wall and an outer wall; and a double wall lid portion connected to said base portion, said lid portion having an inner wall and an outer wall; wherein the inner wall of at least one of said portions has a hole for receiving the object; and wherein the outer wall of the at least one portion having the hole in the inner wall thereof includes a protrusion for engaging the object extending toward the inner wall having the hole therein.
 19. The case of claim 18, wherein the outer surface of said protrusion corresponds to at least part of the outline of the object.
 20. The case of claim 19, wherein the outline of the object is the outline of a tool.
 21. The case of claim 18, wherein the outer surface of said protrusion corresponds to the outline of an aperture in the object.
 22. The case of claim 18, wherein said protrusion is positioned to engage an edge of the object to prevent movement of the object within the case.
 23. The case of claim 22, wherein the position of said protrusion corresponds to at least one of a length and a width of the object.
 24. The case of claim 18, wherein the hole is a punched hole.
 25. The case of claim 24, wherein the hole corresponds to at least part of the outline of the object.
 26. The case of claim 18, wherein said lid portion is integrally formed with said base portion. 